Convert to binary in C++

#include <iostream>
using namespace std;
int main()
{
    int n,i=0,num,t;
    cout<<"Enter a number : ";
    cin>>n;
    while (n!=0)
    {
        if (n%2==1)
        {
            t=1;
            for(int j=0;j<i;j++)
            {t=t*10;}
            num=num+t;
        }
        n=n/2;
        i++;
    }
    cout<<num;
}